1. Field of the Invention
The present invention relates to a character recognition method, program and recording medium.
In recent years, a character recognition technology has been broadly utilized to input characters handwritten or printed on a paper into the computer. In order to indicate entry locations of characters on the paper such as a document, some guide characters or ruled lines (hereinafter referred to as preprint information) are drawn on a paper face to allow the characters to be entered near the guide characters or ruled lines in most cases.
In such cases, it happens that recognizing correctly the entry characters becomes difficult, because of the presence of the preprint information. So the improvements are needed.
2. Description of the Prior Art
FIG. 28 shows an example of characters written over the preprint information. In this example, the characters representing the units of ten million, million, hundred thousand, ten thousand, thousand, hundred, ten and yen for the amount of money, and the ruled lines representing the frames for writing the characters (numbers) corresponding to the units are preprinted, whereby the user can enter the handwritten characters (numbers) on the paper, as shown in the drawing.
The conventional method for recognizing the characters written on the paper including the preprint information will be described below. Using the known information concerning the preprint information, the preprint information is deleted from the read information containing the preprint information to leave behind the entry character information, which is then only recognized. In this case, employing the known information such as the positional information in the area where the preprint characters or ruled lines are present, and the kind of preprint character, the preprint characters or ruled lines can be deleted. In an environment where the document can be read as a gray level image, there is a character recognition method in which if there is a difference in gray level between the preprint information and the characters for recognition, only the characters for recognition are extracted using the difference in gray level to effect the character recognition.
Of the conventional methods as above described, the method of deleting the preprint information had the problem that if there is no knowledge concerning the preprint information, the character recognition can not be performed correctly. Also, even though the preprint information can be extracted by another method, an extraction error may occur in some cases, or when the ruled line or the preprint information remains with the characters for recognition, the character recognition result may be false.
Further, in the case where the document could not be acquired as a gray level image owing to the limitations on the system, or there was no or less difference in gray level between the preprint information and the characters for recognition, there was the problem that the characters for recognition could not be extracted from the gray level information.